/Engine/Source/Runtime/UMG/Public/Blueprint/UserWidget.h
This event is primarily to allow parent widgets to consume an event before a child widget processes it and it should be used only when there is no better design alternative.
Returns whether the event was handled, along with other possible actions
[FEventReply](API\Runtime\UMG\Components\FEventReply) OnPreviewKeyDown ( [FGeometry](API\Runtime\SlateCore\Layout\FGeometry) MyGeometry, [FKeyEvent](API\Runtime\SlateCore\Input\FKeyEvent) InKeyEvent )